A little summary goes a long way.
Nestled between the Title and Teaser fields when editing in Cascade, the Summary field is unique in that it only appears on news story, announcement and feature listing pages. Even though it doesn't show up on every page, there are many benefits packed into that little field, making it a valuable one to not skip over.
Improve search results
The Summary field is what Google wants to show in search results — this includes the W&M Search which is powered by Google. What do you want people to read when your page pops up in the search results? Add it to your Summary field. While the summary can be any length, Google generally shortens it to about 120 characters on mobile and 150 on desktop, so keep that in mind.
Improve social media link previews
When a link to your page is shared on social media, typically a link preview is displayed that pulls in a photo, the title of the page and the summary. If you do not enter a summary, the link preview may use the next available content on the page. Note: For pages with long titles, the Summary field text may not be displayed in the link preview.
Improve Search Engine Optimization (SEO)
The Summary field provides indirect SEO improvements. Good summaries should help click through rates in search and on social media, which should improve your page's SEO performance.